The present invention relates to a display device, and in particular, to a display device having an improved video signal drive circuit.
For example, in an active matrix type liquid crystal display device, a liquid crystal layer is sandwiched between a pair of opposing substrates, formed on a liquid-crystal layer-side surface of one of the pair of substrates are a plurality of gate signal lines extending in an x direction and arranged in a y direction, and a plurality of drain signal lines extending in the y direction and arranged in the x direction, and each of a plurality of pixel areas is surrounded by two adjacent ones of the gate signal lines and two adjacent ones of the drain signal lines.
Each pixel area is provided with a switching element driven by a scanning signal via a gate signal line, and is provided with a pixel electrode supplied with a video signal via the switching element from a drain signal line. The pixel electrode generates an electric field between the pixel electrode and a counter electrode formed on one of the two substrates and thereby controls light transmission through the liquid crystal layer.
One end of each of the gate signal lines is connected to a vertical scanning circuit which sequentially selects one of the gate signal lines based upon the scanning signal. One end of each of the drain signal lines is connected to a video signal drive circuit which supplies a video signal to each of the drain signal lines in synchronism with selection of a corresponding one of the gate signal lines.
Data from an external system such as a microcomputer, for example, are transferred to the video signal drive circuit serially, and then they are supplied to respective ones of the drain signal lines in parallel by a shift register provided within the video signal drive circuit.